mburton2 avatar image
mburton2 asked

75/15 load switching on/off

75/15 controller, fitted in a campervan approx 2 weeks. 100w solar panel is clipped to the roof & connected to controller when needed.

Lastnight on a campsite with electric hookup (2nd time since installation), so solar NOT connected, & 240v charger connected directly to battery.

Anything connected to the 75/15 "load" is pulsing on/off...2seconds off, 4seconds on.

Load is connected (via 6-way fusebox) : phone-chargers, gps-tracker, CB radio...nothing high-power.

The blue LED "Bulk" is flashing about every 3s.

Any ideas?


Hardware firmware:v1.39

Interface V2, firmware:V2.19

Bootloader: V1.10

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3 Answers
kai avatar image
kai answered ·

Not going to comment on how the 75/15 load output works, I haven't played around with it.

From a general fault finding perspective, have you checked the total load current connected to the 75/15 load output - is it possible there is a partial short in the cabling or one of your loads.

Is it possible to temporarily configure so your loads are connected to the battery directly (taking the 75/15 and the 240v charger out of the loop) - does the pulsing still occur? Then put the 75/15 or 240v charger back in, and see when the pulsing appears again.

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simon-bernin avatar image
simon-bernin answered ·

Hi, I have exactly the same problem and haven't found a solution yet. I also contacted Victron direcly. Have you more information already?

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mburton2 avatar image mburton2 commented ·

Not yet.....But my holiday has now Finished, so the urgency is not there now, but I WILL find a this space.

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slydar avatar image slydar mburton2 commented ·

i have this issue as well, had my 75/15 for some years but suddenly it stopped outputting at the load terminals and while it still charges the battery i now have the bluetooth dongle and see the load output flapping on/off... on/off... constantly even with no load connected

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adev avatar image
adev answered ·

firsty: Leave the solar panels connected to the controller at all times (except when maintenance needed). If you DO need to disconnect them, make sure they are not under load (charging) at the time, If they are, cover the panels first, or use the victron connect app to turn off the battery charge function and then turn it back on when the panels are physically reconnected.

2. if you read the manual you should find “...Note (*1): The bulk LED will blink briefly every 3 seconds when the system is powered but there is insufficient power to start charging.”

If you leave the panels connected you should see that happen less, but it is not a problem.

Further, having the panels and the mains charger connected to the battery at the same time is not a problem, they will not fight eachother.

c) What kind of loads are connected to the controllers load terminals? and how thick and long are the cables? Do you have an inverter connected via the terminals?

5. I had a similar issue when I had a dodgy USB lead plugged into one of my USB charges in a 12v “cig lighter” socket.

Unplug all your loads until (hopefullly) the issue goes away. Then plug in loads one by one until the issues returns. You have found the problem load/device.

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mburton2 avatar image mburton2 commented ·

Unfortunately, the panels have to be disconnected regularly, as they are not installed in the camper, but temporarily clamped to the roof-rails when parked up, & removed when travelling...& the panel is also used for other applications, but I will make a note of the "Using the app to turn the battery charger on/off for connecting...Thanks you.

I'm using 60A flex for Load/battery connections (I cant remember the Diameter, but it Only-just fits in a Blue-crimp terminal.. The cable lengths are Short...about 10cm from the Victron-battery output to the battery....about the same from the Victron-Output, to my Fuse-box. From the Fusebox is a GPS-Tracker, CB-radio, 2x2a-USB-charge points, & a 12v power-output, sometimes used to charge phones with a cigar-lighter type charger.

No inverter in the van.

Even with everything unplugged, I can watch the "Output" switch on-off using the App.

Anything powered directly off the leisure battery is OK (Internal l;ights, Tap water pump etc)

I'm wondering if the VSR used for the Split-charge (Between Starter-battery & Leisure battery) has anything to do with it?....It works BOTH ways....If the Starter battery reaches a set level (alternator working), it will then start to charge the leisure battery...AND if the leisure battery reaches a set voltage, it will connect the starter-battery & start to charge that, from the Solar too.....Could that have an effect?

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adev avatar image adev mburton2 commented ·

I’m not familiar with VSRs so I can’t comment on that,

What kind of battery and what sort of voltages is it reading?

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mburton2 avatar image mburton2 adev commented ·

The Starter Battery, is a Bosch Silver-calcium...not exactly sure of the was on the van when I bought it 5 years ago....Normally sits at a high 12V (12.6, 12.7 -ish) at rest.

The leisure battery is 115Ah Halfords-branded Yuasa lead-acid...This is about 1 year old...& again normally sits in the 12.6 - 12.7v region at rest

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